Having million of users pasting your widget all over the Internet and driving traffic back to you site may be a wonderful thing, but are you taking advantage of the white label SEO and linking value you can get from widgets? Probably not.  The concept of using widgets to drive traffic and SEO is not new, but perhaps fundamental to their design. The notion of "widget bait" as a form of link building has been around for sometime. Most of the discussion however has been around increasing widget adoption, which is great, but fails to address the underlining technology and the limitations that need to be overcome to ensure effective widget SEO. Its successful implementation is to be found at https://stellarseo.com/services. Here are some guidelines from Roofing Leads on how to get the best SEO value from your widgets:

• Widget Technology and SEO
  Web-based widgets are generally developed using one of a several internet technologies: Javascript/HTML, Adobe Flash, or IFRAMES. All of these technologies do not lend themselves to exposing their content to search engines. In all of these cases, considering a link inside the widget's embed HTML code. Either under the widget, or in the using a NOSCRIPT (in the case of Javascript widgets).
• Keyworks and Anchor Text
  Consider using relavent keywords in the anchor text. Vary the anchor by randomizing the embed HTML code generation if possible. This "fake-organic" approach makes your data appear more normal in the eyes of a search engine and gives you greater reach with keywords. If possible track and measure which keywords work best and generate the most traffic for your widget/site.
• Consider Other Integrated Approaches
  Consider "native" plug-ins (for Wordpress, Joomla and other blogging platforms) that generate good old "search engine friendly" HTML.
• Take a Platform Approach to Widget SEO
  Tweaking one or two widgets to improve their SEO perform may not be worth the time or effort, but clients using a widget content delivery platform or network (such as Metablocks' Widgetmatic platform) will get more leverage from SEO that is dynamically and automatically generated in their widget embed code!